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TauCeti.AlgebraicGeometry.Scheme.GenericPoint

The generic point of an irreducible scheme and the specialization order #

The points of a scheme are ordered by specialization: x ≤ y when y generizes x. On an irreducible scheme the generic point generizes every point, so it is maximal for this order, and it is the only maximal point: a point with no proper generization is generized by the generic point and generizes it, hence equals it because the underlying space of a scheme is T₀. Since the points of coheight zero are the maximal ones, this identifies the points of coheight zero of an irreducible scheme with its generic point.

Main results #

The generic point of an irreducible scheme is maximal for the specialization order: it generizes every point.

A point of an irreducible scheme which is maximal for the specialization order, that is, a point of coheight zero, is the generic point.

The points of an irreducible scheme which are maximal for the specialization order are exactly the generic point.